Magnetic t-square



. 1,6395 1927' w. B. THOMPSON 8o MAGNETIC T-SQUARE Filed Feb. 32, 1927 &

Zomara IN'VENTOR ATTORNEY WITNESS:

Patented Aug. 16, 1927.

WADE B. THOMPSON, OI DETROIT, MICHIGAN.

MAGNETIC T-SQUABE.

Application filed February 12, 1927. Serial 170. 187,788.

This invention relates to geometrical instruments and particularly to an improvement on the structure of the T-square as disclosed in my Patent No. 1,245,821 patented on November 6th 1917.

The primary object of the present invention is to provide a simplified structure of a T-square ,which includes magnetic means adapted to attract and hold the T-square to 111 surfaces of certain characteristics, so that the hands of the user of the T-square will be free to use other instruments or for any other desired purpose.

This invention also consists in certain other features of construction and in the combination and arrangement of the several parts, to be hereinafter fully described, illustrated in the accompanying drawings and specifically pointed out in the appended claims.

In describing my invention in detail, reference will be had to the accompanying drawings wherein like characters denote like or corresponding parts throughout the several views, and in which:

Figure 1 is a fragmentary top plan view of a T-square which forms the subject matter of the present invention with parts broken away to clearly illustrate the construction. v

Figure 2 is a perspective view of the T- square with the blade broken away.

Figure 3 is a vertical sectional view taken through a drawing board and the head of 5 my improved T-square and showing the application of the latter with the board.

Referring to the drawings in detail the reference numeral 1 indicates the blade which is of the usual construction, and is fixed to the head 2 through the medium of a plurality of screws 3 as best'shown in Figures 1 and 2 of the drawings. The head 2 is provided with recesses 4 disposed upon opposite sides of the point of connection of the blade 1. therewith to receive horse shoe magnets 6 which have their poles formed wit annular grooves 7 having inwardly inclined side walls so as to be fixed in openings 8 formed in a metallicstrip 9 fixed to the inner surface of the head through the medium of screws 10 as best shown in Figure 1 of the drawings.

While I have disclosed a drawing board 12 having secured to its edges a'strip 13 of magnetic material for cooperative associa tion with the magnets, I wish it to be clearly understood that the T-square as shown may be used directly on iron structures that are being erected.

From the above descri tion and disclosure in the drawings, it will obvious that my improved T-square is extremely simple, yet functions adequately and effectively to hold itself to a drawing board provided with the magnetic strip 13, or to iron or steel beams or other pieces of iron structure so that the hands of the user of the T-square may be free to use other instruments or for any other desired purpose as above set forth.

It is thought from the foregoing description that the advantages and novel features of my invention will be readily apparent.

I desire it to be understood that I may make changes in the construction and in the combination and arrangement of the several parts, provided that such changes fall within the scope of the appended claims.

What I claim is: I

1. A T-square of the character described comprising a blade, a head fixedly secured thereto and being provided with recesses along its contact face, horse shoe magnets in the respective recesses and a metallic stripsecured to the said face and receiving the poles of the horse shoe magnet for the purpose specified.

2. A T-square of the character described comprising a blade, a head therefor, horse shoe magnets arranged in said head, means secured to the contact face of said head and receivingv the poles of said magnets, and said poles passing through said means and adapted for attracting and holding the magnet to surfaces of certain characteristics.

3. A head for a T-square, said head being provided with recesses arranged along its. contact face, horse shoe magnets disposed in the respective recesses, a metallic strip secured to said face and being provided with 100 openings, and said magnets having their poles rovided with annular grooves formed with inclined surfaces to be secured in said openings.

4. A T-square of the character'described comprisin a blade, a head secured to said,

blade and ing provided with recesses along its contact face, a strip having spaced pairs of openings arranged therein and being secured to said face, magnets arranged in said 10 recesses and passing through the respective openings for association with magnetic material whereby the T-square will be held I in fixed relation to said material.

In testimony whereof I afiix my si ature.

WADE B. THOMP ON. 

